Issue with ungrib.exe

[Raha]

Hi, I hope this message finds you well.
I am currently working on setting up WRF using ERA5 data, and I’ve encountered a problem when processing single-level data with ungrib.exe.
I have downloaded two datasets from the CDS API (I attached the scripts)

• One for pressure levels using the reanalysis-era5-pressure-levels product.
• One for single levels using the reanalysis-era5-single-levels product.

Each dataset was processed separately with its own Vtable. However, when I attempt to run ungrib.exe using the Vtable created for the single-level data, I get the following error:
*** Starting program ungrib.exe ***
Start_date = 2008-08-20_00:00:00 , End_date = 2008-08-20_23:00:00
output format is WPS
Path to intermediate files is ./

###############################################################################

Inventory for date =

PRES TT UU VV SPECHUMD DEWPT RH LANDSEA SOILGEO SOILHGT PSFC PMSL SKINTEMP SEAICE SST SNOW_DEN SNOW_EC SNOW SNOWH ST000007 ST007028 ST028100 ST100289 SM000007 SM007028 SM028100 SM100289
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
Subroutine DATINT: Interpolating 3-d files to fill in any missing data...
Looking for data at time 2008-08-20_00
ERROR: Data not found: 2008-08-20_00:00:00.0000

Could you please help me understand:

1. Why is this error occurring despite the presence of data?
2. Is it necessary to run ungrib separately for pressure and surface datasets, and how should I combine the intermediate files?
   

 

[Kenny_P]

For question 2, yes you do need to ungrib separately for pressure and surface datasets. I would recommend you take a look at the steps listed in the thread: How to use ERA5 Data From Copernicus Database

 

[Raha]

I followed the instructions from the link you provided for processing my GRIB data using WPS. However, when I attempt to run ungrib.exe, I encounter the following error:

*** Starting program ungrib.exe ***
Start_date = 2008-08-20_00:00:00 , End_date = 2008-08-20_23:00:00
output format is WPS
Path to intermediate files is ./
*** stopping in gribcode ***
I was expecting a Grib1 file, but this is a Grib2 file.
It is possible this is because your GRIBFILE.XXX files
are not all of the same type.
WPS can handle both file types, but a separate ungrib
job must be run for each Grib type.
STOP gribsize in gribcode


I believed my data was in GRIB1.
Any guidance on resolving this issue would be greatly appreciated.

 

[Kenny_P]

In your WPS folder, do you see more than 1 GRIBFILE.XXX files? You should only see 1 (Either your surface or pressure level data you linked).

I would delete any GRIBFILE.XXX in your WPS folder, then link the pressure grib file then try to ungrib again.

 

[Raha]

thanks. I deleted all GRIBFILES and re-download Pressure level data . then follow the top link that you sent and the ungrib.exe and metgrid.exe worked successfully.

 

[Ming Chen]

NCAR RDA provide ERA5 data on both pressure level and model level. Please see tge download page:
NCAR RDA Dataset d633000

We provide a python package to process the ERA5 data:
GitHub - NCAR/era5_to_int: A simple Python script for converting ERA5 model-level netCDF files to the WPS intermediate format

I suppose using this package to process ERA5 is a better for you.

Would you please try and let me know if you have any issues?

Thanks.